In one of Ole Gunnar Solskjaer’s first public messages to his players after becoming Manchester United manager, the Norwegian insisted there were some squad members who would have to take his own lead in grabbing opportunities however they present themselves.Famed as a super-sub during his 11-year spell as a player with the Red Devils, Solskjaer scored 29 of his 126 United goals after coming off the bench, most memorably when netting the injury-time Champions League winner in 1999.And he was quick to warn his players that some will have to become impact players for the team cause. 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That’s always my comeback to players,” he explained. “You never know, you might come on and make an impact and grab the opportunity when you get it.”And as he takes his United side to Wembley on Sunday to play Tottenham in what is his first meeting with a top-six club, he is faced with the prospect of choosing between Romelu Lukaku and Marcus Rashford for a spot in the main striker’s spot.Rashford’s form of late has been electric, and alongside Anthony Martial and Jesse Lingard he has been a key part of a frightening strike-force abundant in pace, intelligence and deadliness in front of goal.The Solskjaer effect has most been summed up by United’s increased traffic in the final third, and Rashford has been like a man possessed under the new gaffer.But during his first five games in charge, the manager has had it relatively easy in terms of making the call between the England front man and Lukaku thanks to the latter’s absence for a spell of compassionate leave.Since returning to the club just before the New Year began, Lukaku has played the role of super-sub in two league games before being handed a start as one of nine changes for the 2-0 FA Cup win over Reading last weekend.By scoring in all three of those appearances, the £75 million signing has given Solskjaer food for thought, but that may have worked in both a positive and a negative sense for Lukaku in his quest to regain his spot as the unquestioned first choice in the number-nine position.Under Jose Mourinho, Lukaku was for a long time the only player even considered to lead the line. Just as he had done with Zlatan Ibrahimovic in 2016-17, the Portuguese gave Lukaku free reign to work the centre of the attack and held back Rashford and Martial in a platoon for the left-wing spot.But by proving his effectiveness in coming off the bench in the games against Bournemouth and Newcastle over the New Year period, Lukaku may have made a rod for his own back. Because while Rashford has looked like a new man thanks to the faith entrusted in him by Solskjaer, the Belgium international has not done enough in his general play to suggest that he can play the more rounded striking role that his new manager is craving.United’s sharp, neat passing style under Solskjaer needs more than a heavy Lukaku first touch around the 18-yard box. When the full-backs are urged to get forward more often to deliver balls into the centre, there can be no getting caught on your heels as can too often be the way with the former Chelsea and Everton frontman.At this moment in time, Solskjaer’s style of football – is anybody calling it Ole-ball yet? – demands a Rashford rather than a Lukaku in the final third. Lukaku remains a good option to turn to if United need something different as happened at Newcastle last week, but he cannot claim to have overly impressed in terms of his all-round play under the new boss so far.There is always a spotlight to consider when a manager makes the decision to bench an expensive footballer but that cannot even come into the equation at this point, and from his opening few weeks at Old Trafford Solskjaer does not seem the type to allow such a thing to enter his thoughts.What he needs is to find the best way to overcome Spurs on Sunday, and that seems unlikely to be playing to Lukaku’s needs when he can have Rashford playing to United’s needs far more effectively. In many ways he now ought to be considered in the sort of light that Marouane Fellaini revelled in under Mourinho – when there needs to be a new approach, Lukaku is your first port of call.It is a role Solskjaer knows only too well, and while it might get somewhat grating for Belgium’s number-one striker if he continues to find himself on the bench every week, that is the reality of his situation right now.All he can do is do everything that Solskjaer is asking of him and then his opportunities will come. But as for Sunday, it must be Rashford who continues to lead United’s new dawn under their baby-faced boss and Lukaku who is left to make the kind of impact which made his manager a legend. Check out Goal’s Premier League 2019-20 fantasy football podcast for game tips, debate and rivalries.